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Biomedical subjects

M Fontana

Publications and source records attributed to M Fontana.

At least 73 records · Page 4Linked to original sources
PubMed1996

Antigliadin antibodies in HIV-infected children.

Immunoglobulin A-antigliadin antibodies and total immunoglobulin A were assessed on serum samples from 52 children infected by Human Immunodeficiency Virus (HIV). Titers of antigliadin antibodies exceeding the normal range were found in 14 children (27%). No statistically significant difference was observed either between children with symptomatic or asymptomatic infection, or among children with different degrees of immunosuppression. Though total immunoglobulin A concentration increased with the progression of the disease, no significant correlation was found between antigliadin antibodies and total immunoglobulin A. Mean antigliadin titers showed no significant difference between children with or without chronic gastrointestinal complaints. These findings suggest that, although a raised immunoglobulin A-antigliadin activity is a common feature of children infected by HIV, this is not merely the consequence of elevated total immunoglobulin A concentration. Moreover, in these children a raised antigliadin antibody titer should not be regarded as a reliable marker either of disease progression or of intestinal mucosa damage.

Biomarkers↗
PubMed1996

[Polymyalgia rheumatica associated with myelodysplasia].

In this paper we describe a patient, female 76 years aged, who showed typical symptomatic, haematologic and instrumental findings of polymyalgia rheumatica. The patient also showed myelodysplastic syndrome and peripheral signs of vasculitis, which some authors refer in association with PMR. The improvement obtained with steroidal therapy confirmed the clinical picture of case.

Aged↗
PubMed1996

[Motility of the gastric antrum and the gallbladder following oral administration of sulfate-bicarbonate].

The authors evaluate the influence of a sulphate-bicarbonate mineral water on gastric emptying and cholecystic motility. Nine healthy volunteers drunk at settled intervals and with same procedures equal doses of mineral water and tap water on alternate days. Ultrasonographic evaluation of the gastric emptying and cholecystic volumes was performed before and after mineral water and top water drinks at settled intervals. The mean values of the gastric and the cholecystic volumes were calculated and compared at the single times. The results showed a significant colecystocinetic effect of the mineral water compared with tap water. No difference was observed in the gastric emptying with the mineral and tap water. Our work contributes to the knowledge of the pharmacodynamic effects of the mineral water employed and confirms its usefulness in the syndromes based on alterations in bile secretion and bile excretion in duodenum.

Administration, Oral↗
PubMed1996

Beta-adrenoreceptor blocking heterocyclic oximes and ethers.

This paper reports synthesis and pharmacological properties of thienyl, pyrrol, indolyl and benzofuryl-O-(3-alkylamine-2-hydroxypropyl)oximes and some 3-(3-alkylamine-2-hydroxypropyl)alkyloxy indoles aiming to study the influence of five membered and condensed heterocyclic substituents on the beta-adrenoreceptor inhibiting potency. All heterocyclic derivatives synthesized (1-17) were less active than the reference propranolol on the rat heart, while showed a comparable potency on the guinea pig trachea, exhibiting a significant beta 2-selectivity. The low beta-blocking potency of the five membered derivatives seemed to confirm the negative influence of the polarization of the oximic carbon in the binding with non polar region of the beta-adrenoreceptor. Another important interaction could take place with the enzyme adenyl-cyclase which is responsible of the signal of transduction. It could be hypothesized that the heteroatom of the heterocyclic nucleus acted as an electron-donor group and engaged a coordinative bond with magnesium atom present on the adenylcyclase system, responsible of the agonist activity. The pharmacological in vivo experiments and the binding results were in accordance with the in vitro data.

Adrenergic beta-Antagonists↗
PubMed1995

Indium-111 octreotide scintigraphy in neurofibromatosis.

Scintigraphy with the radiolabelled somatostatin analogue indium-111-DTPA-D-Phe-1-octreotide has recently been proposed for the imaging of CNS neoplasms expressing somatostatin receptors. While meningiomas are imaged with high sensitivity, neurinomas do not take up octreotide owing to the lack of somatostatin receptors. Neurofibromatosis is a relatively uncommon disorder in which meningiomas and neurinomas often occur in the same patient. Differential diagnosis between these two tumours by computed tomography and magnetic resonance imaging can be difficult. This study reports on 111In-octreotide scintigraphy in four patients with neurofibromatosis. 111In-octreotide scintigraphy was shown to be very helpful in the in vivo differential diagnosis: all four meningiomas showed intense tracer uptake, while all 15 neurinomas were negative (P < 0.001 by Fisher's exact test). It may be concluded that scintigraphy with 111In-octreotide is a useful diagnostic procedure in neurofibromatosis, complementing standard neuroradiological imaging procedures.

Adolescent↗
PubMed1995

Human intestinal cryptosporidiosis: secretory diarrhea and enterotoxic activity in Caco-2 cells.

A cell line model to detect enterotoxic effect was used to test fecal specimens of patients with enteric cryptosporidiosis. Fecal samples were obtained from 11 patients with Cryptosporidium diarrhea, and osmotic gap was determined. Caco-2 cell monolayers grown on filters were mounted in Ussing chambers, and electrical parameters were measured before and after the addition of fecal supernatant. A significant increase in short-circuit current was seen in 9 of 11 specimens. The enterotoxic effect was time- and dose-dependent, saturable, and Cl(-)- and Ca(2+)-dependent. Fecal osmotic gap was consistent with secretory diarrhea in the 9 enterotoxin-positive but not in the 2 enterotoxin-negative samples. In conclusion, a cell line model for studying the pathophysiology of enteric cryptosporidiosis was established. Enterotoxic activity was observed in most patients with enteric cryptosporidiosis and was strictly associated with secretory diarrhea.

Adult↗
PubMed1995

Characterization of preparations enriched for Streptococcus mutans fimbriae: salivary immunoglobulin A antibodies in caries-free and caries-active subjects.

The ability of bacteria to adhere to salivary pellicle-coated enamel tooth surfaces is a critical step in oral bacterial colonization. Oral bacteria adhere to receptors of host origin in salivary pellicle. Streptococcus mutans has been identified as the major etiological agent of human dental caries and composes a significant proportion of the oral streptococci in carious lesions. Bacterial fimbriae are small (100 to 300 nm) hairlike appendages emanating from the cell surface. Preparations enriched for S. mutans fimbriae were isolated by a shearing technique and alternating high- and low-speed centrifugations. A representative fimbrial preparation had two distinct double bands comprising four proteins of approximately 100 to 200 kDa and one faint band at 40 kDa on reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis/immunoblots and had demonstrable glucosyltransferase activity. Rabbit antisera raised against the preparation specifically stained the fuzzy coat of S. mutans, demonstrating short fimbria-like structures protruding 100 to 200 nm from the cell surface. Controls without antifimbria antibody did not exhibit this staining. There were significantly higher (P < or = 0.05) levels of salivary immunoglobulin A, but not serum immunoglobulin G, antibodies to the enriched S. mutans fimbria preparation by enzyme-linked immunosorbent assay from caries-free subjects than from caries-active subjects. The results suggest that S. mutans fimbriae may be an important adherence factor to which caries-free subjects mount a protective salivary immune response.

Animals↗
PubMed1995

[Current orientation in medical management of ulcerative colitis].

Authors synthetically remind epidemiology, eziopathogenesis and clinic of ulcerative colitis; they after describe the drugs employed in therapy of disease, stressing the mechanism of action, efficacy, collateral effects. Authors remember the choice of cortisonic therapy in the acute and severe periods of disease and the specific activity of salazopyrine and its metabolite 5-aminosalycilic acid in the ulcerative colitis and refer about the use of drugs as immunodepressors, fatty acids omega 3, zileuton, short chain fatty acids. Practical patterns of therapy in the diverse stages and clinical forms of the disease are exposed.

Adrenal Cortex Hormones↗
PubMed1994

Aminoethylcysteine ketimine decarboxylated dimer protects submitochondrial particles from lipid peroxidation at a concentration not inhibitory of electron transport.

In contrast with other inhibitors of the NADH dehydrogenase of the respiratory chain, the decarboxylated dimer of aminoethylcysteine ketimine protects bovine heart submitochondrial particles (SMP) from the NADH-Fe(+3)-ADP-induced lipid peroxidation. This effect, measured as inhibition of malondialdehyde formation, is concentration-dependent in the range 0.02-0.2 mM. This range of concentration is not inhibitory on NADH-oxidase activity of SMP. Furthermore the dimer is able to counteract the malondialdehyde formation stimulated by the Complex I inhibitors rotenone and N-methyl-4-phenylpyridinium (MPP+).

Amino Acids, Sulfur↗
PubMed1994

Aminoethylcysteine ketimine decarboxylated dimer inhibits mitochondrial respiration by impairing electron transport at complex I level.

The product of the spontaneous dimerization and decarboxylation of aminoethylcysteine ketimine (simply named the dimer in this note) has been investigated for a possible biochemical activity. It has been found that the dimer inhibits the ADP-dependent oxidation of NAD(+)-linked substrates in rat liver mitochondria and electron transport from NADH to O2 in bovine heart submitochondrial particles (SMP). Oxidation of succinate by SMP is not impaired by concentrations of the dimer inhibiting almost totally NADH oxidation. Furthermore, the dimer did not affect the rotenone-insensitive electron transfer from NADH to menadione. These results give a preliminary indication suggesting that the dimer inhibits electron flow from NADH dehydrogenase to ubiquinone at or near the rotenone binding site(s). The dimer inhibition falls in the same range exhibited by some neurotoxins which are known to interact with the rotenone binding site.

Animals↗
PubMed1994

[Chronic obstructive bronchopneumopathy. Epidemiologic aspects and balneotherapy potential].

The authors remember the epidemiological data of BPCO in Italy and in the world and stress the increasing incidence and prevalence of these disease, interesting above all industrial-urban areas, middle and old aged, males and smokers. The pathogenetic role of atmospheric pollution, caused by industries, heating system and motor vehicles, in exposed. At the end Auctors summarise the results of the inhalatory therapy by mineral waters in BPCO, especially of sulphureas and salso-jodic spas.

Balneology↗
PubMed1994

Vitamin C (ascorbic acid): clinical implications for oral health--a literature review.

This article reviews the chemistry, functions, and toxicity of vitamin C, as well as its food sources, recommended daily allowance, and laboratory biochemical findings, to help clinicians understand and recognize its systemic and oral deficiency manifestations. An understanding of these topics will help the general dentist, periodontist, and oral surgeon appropriately prescribe vitamin C for their patients.

Animals↗
PubMed1994

[Evaluation of exocrine pancreatic insufficiency in cirrhotic patients,using the fecal chymotrypsin test].

In spite of having been the object of a number of studies, the association of morphologic and functional alterations of the pancreas with liver cirrhosis is as yet controversial. Therefore, the authors have studied exocrine pancreatic function in 40 patients: 8 with alcoholic cirrhosis, 18 with non-alcoholic cirrhosis, and 14 without evidence of hepatobiliary and pancreatic pathology. Pancreatic function was studied by the fecal chymotrypsin test which is sufficiently sensitive and specific and has been preferred in view of its practicability and non-invasiveness. Analysis of the results showed pathologic values to be significantly more frequent in subjects with alcoholic cirrhosis (50%, p < 0.05) compared to non-alcoholic cirrhotics (11.11%) and to controls (7.2%). These findings go to show that pancreatic exocrine deficit is frequently associated with alcoholic cirrhosis, thus confirming what has already been known about the pathogenetic role of alcohol which is apt to provoke both hepatic and pancreatic damage. Finally, it should be pointed out that pancreatic exocrine deficit is a purely functional alteration without clinical manifestations.

Aged↗
PubMed1993

Characterization of [35S]lanthionine ketimine specific binding to bovine brain membranes.

[35S]Lanthionine ketimine binds specifically and with high affinity to bovine brain membranes. This binding has been studied in detail. It is reversible, not occurring at an uptake site or at a metabolizing enzyme and depending only weakly from ionic strength; it is affected by thiol reagents. [35S]Lanthionine ketimine specific binding is displaced only by other ketimines and by catecholamines, but not by more selective adrenergic ligands; binding parameters are reported. [3H]Adrenaline but not [3H]dihydroalprenolol is partially displaced by lanthionine ketimine. With bovine brain preparations a significant stimulation of basal adenylate cyclase activity by lanthionine ketimine is observed.

Adenylyl Cyclases↗
PubMed1993

Ultrastructural changes in the duodenal mucosa of HIV-infected children.

We studied the ultrastructure of duodenal biopsy specimens from six HIV-infected children with chronic gastrointestinal symptoms. A monomorphic pattern of microvillar damage (short and irregular microvilli, joined at their bases) was seen in all cases, even when the mucosa was normal on conventional histology. Among nine HIV antibody negative children, a similar pattern was seen only in three out of four celiac children with severely atrophic mucosa. No viral, bacterial, or protozoan pathogen was found. In HIV-infected children tubuloreticular inclusions were also seen in endothelial cells. These ultrastructural changes could help to account for the gastrointestinal symptoms in HIV-infected children.

Biopsy↗
PubMed1993

Ranitidine pharmacokinetics in newborn infants.

Few data are available for ranitidine pharmacokinetics in the first few days of life. Twenty seven newborn infants were treated with intravenous ranitidine because they were vomiting blood, although they had a negative Apt's test. Each infant provided two blood samples at randomly selected times 30-360 minutes after a 2.4 mg/kg intravenous bolus of ranitidine. A single exponential equation for the concentration-time graph was fitted to the mean serum concentrations at different times. From this model the following mean (SD) measurements wer derived: elimination half life, 207.1 (19.1) minutes; total volume of distribution, 1.52 (0.91) l/kg; and total plasma clearance, 5.02 (0.46) ml/kg/min. Assuming that these measurements do not change with different administered doses, regimens can be derived to assist in planning ranitidine treatment in newborn infants.

Gastrointestinal Hemorrhage↗